Voltage regulators are often used to provide stable power supplies for integrated circuitry, such as microprocessors, logic circuitry, digital signal processors (DSPs), and other circuitry. In an example, a DSP draws a current from the voltage regulator. However, the power consumption of the DSP may vary, causing current spikes that radiate electromagnetic interference (EMI) through magnetic coupling between the power input and nearby receiver circuitry.
One approach for smoothing variations in the input current includes increasing an amount of on-chip charge storage capability, either by adding de-coupling capacitors or by increasing a capacitance of de-coupling or filter capacitors. However, large capacitors increase the cost of the circuit device. Another approach includes regulating the current, which regulation may cause the voltage supplied to the load, such as the DSP, to vary. Such variations can introduce over-voltage and/or under-voltage conditions, which can impact DSP performance. To avoid such under-voltage conditions, the voltage regulator often provides a maximum supply current, regardless of the power consumption of the DSP. However, such maximum supply currents consume more power than is necessary to operate the DSP. Hence, there is a need for a power efficient, digital voltage regulator that is cost effective and that provides high quality regulation.